小白书贪心之区间选点问题

#include<cstdio>
#include<cstring>
#include<cmath>
#include<cstdlib>
#include<string>
#include<set>
#include<map>
#include<iostream>
#include<algorithm>
using namespace std;
const int maxn=1e6+10;
const double eps=1e-5;
struct node
{
int x,y;
}a[maxn];
bool cmp(node a,node b)
{
if(a.y==b.y)
return a.x>b.x;
return a.y<b.y;
}
int n;
int main()
{
cin>>n;
for(int i=0;i<n;i++)
scanf("%d%d",&a[i].x,&a[i].y);
sort(a,a+n,cmp);
int sum=0;
int end=-1;
for(int i=0;i<n;i++){
if(a[i].x>end){
end=a[i].y;
sum++;
}
}
cout<<sum<<endl;
}